中尺度模式探空资料在北京局地暴雨预报中的应用

Application of mesoscale model-generated sounding in Beijing local rain storm forecasting

结合北京局地暴雨特点,重点分析北京两次局地强暴雨过程的中尺度模式探空资料的特征与应用,同时简单讨论模式探空与降水量预报可能存在不协调的原因。结果表明:1)有利于北京局地暴雨发生的模式探空资料的主要特征是:对流层低层850 hPa以下水汽含量较充足,层结温度线与干绝热线近于平行,地面温度高(大于31℃);对流层中高层650 hPa以上相对冷干,对流层中低层800—600 hPa存在有利于深对流发生发展的饱和或准饱和层。2)模式探空资料可以正确反映强降水时间分布、降水性质及不同性质降水之间转换等,由于模式自身存在的协调性问题,在局地暴雨预报中有必要重视对模式探空资料的分析。3)上述结论是在两次暴雨过程分析的基础上得到的,今后仍需通过更多个例来进一步考察。

According to the features of the local rainstorm in Beijing,this paper mainly analyzed the features and application of mesoscale model-generated sounding of two cases of local rainstorm in Beijing,also a preliminary discussion of the factors which could result in the disagreement of implication between sounding and rainfall forecast was given.The results show the following：（1） the features of the mesoscale model-generated sounding implying the rainstorm are as follows.The troposphere in lower level contains sufficient moisture to support the deep convections.The stratification curve is parallel to the dry adiabat with ground temperature warmer than 31 ℃,and it is relatively dry and cold above 650 hPa.There is a saturation or quasi-saturation level between the 800-600 hPa in the middle and lower troposphere,which is beneficial for occurrence and development of deep convection.2） The model-generated soundings can provide a useful implication of the temporal distribution of rainstorm,the characteristics of the rain,and the transition from convectional rain to continuous rain.It is necessary to pay more attention to analyze the model-generated sounding due to the possible disagreement between the rainfall and the sounding.3） The above conclusions are made based on two cases,and further investigation of more cases is needed.